Peroxygen bleach-containing compositions have been described in laundry applications as laundry detergents, laundry additives or even laundry pretreaters.
Indeed, it is known to use peroxygen bleach-containing compositions in laundry treatment applications to boost the removal of encrustated stains/soils which are otherwise particularly difficult to remove, such as grease, coffee, tea, grass, mud/clay-containing soils and the like. However, we have found that a drawback associated with such peroxygen bleach-containing compositions is that said compositions may damage fabrics, resulting in loss of tensile strength, especially when used in pretreatment application, i.e. when applied directly (neat) onto the fabrics, and left to act onto said fabrics for prolonged periods of time before washing the fabrics.
It is thus an object of the present invention to provide improved fabric safety upon bleaching, especially in pretreatment applications where the compositions are left neat into contact with the fabrics for prolonged periods of time before washing.
Indeed, when bleaching fabrics with a composition comprising a peroxygen bleach like hydrogen peroxide, it has been found that the presence of metal ions such as copper and/or iron and/or manganese and/or chromium on the surface of the fabrics and/or the exposure to UV radiation from sunlight of the fabrics after having been contacted with the peroxygen bleach-containing composition, produces fabric damage resulting in loss of tensile strength of the fabric fibres. Indeed, it is speculated that the presence of metal ions such as copper and/or iron and/or manganese and/or chromium on the surface of the fabrics, especially on cellulosic fibres, and/or the exposure of the fabrics to UV radiation from sunlight catalyses the radical decomposition of peroxygen bleaches like hydrogen peroxide. Thus, it is believed that a radical reaction occurs on the surface of the fabric with generation of free radicals, which results in loss of tensile strength.
It has now been found that improved fabric safety can be achieved by formulating a bleaching composition where hydrogen peroxide is substituted by selected hydroperoxides as the bleaching agent, or mixtures thereof.
U.S. Pat. No. 5,284,597 discloses a composition for treating soft surfaces, essentially carpets, which comprise amongst other things tertiary alkyl hydroperoxide. The compositions are said to be safer to colors.
U.S. Pat. No. 3,574,519 discloses the bleaching of textiles where the bleaching agent is an organic hydroperoxide. Organic hydroperoxides are said to be economically attractive. '519 does not discuss the problem of safety to fabrics.
BE 831.277 discloses the bleaching of textiles with the help of a mixtures of bleach activators, one of which being from the class of triazine hydroperoxides. Triazine hydroperoxides are said to be potentially damaging to the colors of fabrics. '277 does not discuss the problem of safety to fabrics.
U.S. Pat. No. 3,753,915 discloses the bleaching of fabrics with a granular composition comprising salts of hydroperoxides. '915 does not discuss the problem of safety to fabrics.